Hamer Fires 5 Series: Basset 5 / 5 Tall - Catalog - Page 14
VENTILATION
Flue Draught Interference
Flue draught interference can be caused by the operation of mechanical extract ventilation fans/systems,
ceiling fans, tumble driers, and other open combustion appliances installed in or adjacent to the
appliance location. In natural draught appliances, this interference can result in the spillage of
combustion products. Smoke Test Type 2 will determine if this is the case. Although 昀氀ue draught
interference is less likely to cause leakage in forced draught appliances, the appliance's operation may
still be affected. If you suspect that the 昀氀ue of a forced draught appliance is being compromised by room
depressurisation, measure the 昀氀ue draught while all mechanical extract systems, ceiling fans, tumble
driers, and any other open combustion appliances in the area are in operation. An insuf昀椀cient 昀氀ue
draught likely indicates that the permanent air supply provision is inadequate.
Spillage Test Under Refuel Conditions
To perform a commissioning spillage test under refuel conditions, follow this procedure:
1. Start the Fire: Light a 昀椀re in the appliance using the recommended amount of kindling or small logs
and set the air control to the manufacturer’s recommended position. Allow the appliance to reach its
normal operating temperature.
2. Seal the Area: Close all external doors and windows, ensuring any openable ventilators or trickle vents
are also closed.
3. Conduct the Test: Open the appliance door and, using a smoke pen or match, pass smoke along the
top and side edges of the combustion chamber opening.
4. Observe: Record whether the smoke and combustion products are drawn into the appliance and up
the chimney, or if they spill back into the room.
5. Finish: Close the appliance door once observations are complete.
6. Repeat with Extraction: Repeat steps 1–5 with all extract systems running on full, ensuring that all
doors to rooms with extraction fans are open during the test.
If the test results show that combustion products are entering the room, remedial action must be taken
to protect occupants from ongoing spillage. This may include adding additional ventilation. A simple
check is to gradually open a window in the room where the appliance is installed and observe whether
the spillage stops. If the problem is resolved by this measure, it will be necessary to install an additional
permanent ventilator.
If the smoke continues to be drawn through the appliance, inspect the baf昀氀e arrangement and the
connecting pipe/昀氀ue for any signs of signi昀椀cant blockage. Further assessment of the installation may
then be required.
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SISB5 - REV1.7 / Issue Date 09-04-2025
